WO2012044129A2

WO2012044129A2 - Method and apparatus for providing multi-media broadcast multicast services data to user equipments over relay nodes

Info

Publication number: WO2012044129A2
Application number: PCT/KR2011/007286
Authority: WO
Inventors: Satish Nanjunda Swamy Jamadagni; Rahul Suhas Vaidya
Original assignee: Samsung Electronics Co., Ltd.
Priority date: 2010-09-30
Filing date: 2011-09-30
Publication date: 2012-04-05
Also published as: WO2012044129A3; US20130182631A1; US9084223B2

Abstract

The present invention provides a method and apparatus for providing multi-media broadcast multicast services (MBMS) data to user equipments in a multi-media broadcast over a single frequency network (MBSFN) environment over relay nodes. In one embodiment, a method includes periodically evaluating a synchronization delay associated with relay nodes in a MBSFN area by a DeNB, and assigning resources to the relay nodes for communicating MBMS data. The method also includes setting a time stamp in synchronization packets based on the synchronization delay, where the time stamp information indicates start time for synchronized transmission of the MBMS data to user equipments in the MBSFN area over an air interface. The method further includes transmitting the synchronization packets including MBMS data and time stamp information to the relay nodes using the allocated resources such that the MBMS data is synchronously transmitted to the user equipments by the relay nodes.

Description

METHOD AND APPARATUS FOR PROVIDING MULTI-MEDIA BROADCAST MULTICAST SERVICES DATA TO USER EQUIPMENTS OVER RELAY NODES

The present invention relates to the field of Multi-media Broadcast/Multicast Services (MBMS), and more particularly relates to providing MBMS data to user equipment in a Multi-media Broadcast over a Single Frequency Network area.

In a Multi-media Broadcast over a Single Frequency Network (MBSFN), Multi-media Broadcast/Multicast Services (MBMS) provide simultaneous delivery of multimedia content (e.g., Television Content, Films, news content) to a large set of user equipments in a MBSFN area via a group of cells. The multi-media broadcast services can be received by any subscriber (e.g., user equipment) located in the MBSFN area in which the service is offered while the multi-media multicast services can only be received by user equipments having subscribed to the MBMS and having joined the multicast group associated with the MBMS. Both the services are unidirectional point-to-multipoint transmissions of MBMS data and can be highly applied to broadcast text, audio, picture, video from Broadcast Multicast Service Centre (BM-SC) to any user located in the service area.

Typically, a group of cells in the MBSFN area are configured to provide MBMS data to user equipments in a time synchronized manner. In other words, the group of cells are having same frequency band allocated with contiguous coverage such that the cells are able to be synchronized and have the capability of transmitting MBMS data in a single frequency network mode.

In E-UTRAN also known as Long Term Evolution (LTE), self backhauling is one of relaying techniques in which a wireless base station is wirelessly connected to the remaining part of a network via another cell which is controlled by an evolved NodeB (eNB), commonly known as donor eNB (DeNB). A wireless base station also known as relay node may constitute one or more cell of its own or may be used to extend cells covered by the DeNB.

The self-backhauling concept implies that the link between the donor eNB and the relay node can operate in the same frequency spectrum, i.e. frequency-overlapped with the radio access links that provide access for User Equipment (UEs) within the donor cell and the UEs within the cell(s) controlled by the relay node. Typically, the radio technology used for the self-backhaul link is basically similar to the one used within the donor cell and the cell(s) of the relay node respectively. For example, in case the donor eNB and the relay node use the LTE radio access technology for communicating with UEs within their cell(s), the self-backhaul link should also be LTE-based or at least based on an LTE-like radio technology.

Multiple such relay nodes may be employed under a single DeNB to extend cells covered by the DeNB. The relay nodes associated with the DeNB may be a part of a MBSFN area that includes eNBs and DeNBs. Alternatively, the relay nodes associated with the DeNB can be a part of separate MBSFN area as illustrated in Figure 1.

Currently, none of the relay nodes are used for synchronized transmission of MBMS data to its UEs along the eNBs and the DeNBs in an MBSFN area. This is due to the fact that a MBMS Control Entity (MCE) (e.g., entity responsible for allocation of time and frequency resources for MBMS data transmission) is not connected to the relay nodes in the existing 3GPP architecture and the DeNB associated with the relay nodes does not have appropriate capabilities to provide the MBMS data to user equipments connected through relay nodes in a synchronized manner.

The present invention provides a method and system for providing multi-media broadcast multicast services (MBMS) data to user equipments over relay nodes.

Figure 1 is a schematic diagram illustrating a MBSFN environment in which relay nodes are part of separate MBSFN area, in the context of the invention.

Figure 2 illustrates a block diagram of a wireless communication system for providing multi-media broadcast multicast services (MBMS) data to user equipments via relay nodes, according to one embodiment.

Figure 3 illustrates a process flowchart of an exemplary method of providing MBMS data to user equipments via relay nodes in a time synchronized manner, according to one embodiment.

Figure 4 is a process flowchart illustrating an exemplary method of counting number of user equipments associated with each of the relay nodes, according to one embodiment.

Figures 5A and 5B are schematic representations illustrating synchronization data packets transmitted to the relay nodes by the proxy MBMS gateway, according to one embodiment.

Figure 6 is a flow diagram illustrating an exemplary method of initiation of a MBMS session for providing MBMS data to user equipments via relay nodes, according to one embodiment.

Figure 7 is a flow diagram illustrating an exemplary method of initiation of a MBMS session for providing MBMS data to user equipments via relay nodes, according to one embodiment.

Figure 8 is a flow diagram illustrating an exemplary method of initiation of a MBMS session for providing MBMS data to user equipments via relay nodes, according to one embodiment.

Figure 9 illustrates a block diagram of a donor eNodeB showing various components for implementing embodiments of the present subject matter.

The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

In the following detailed description of the embodiments of the invention, reference is made to the accompanying drawings that form a part hereof, and in which are shown by way of illustration specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that changes may be made without departing from the scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims.

Figure 2 illustrates a block diagram of a wireless communication system 200 for providing multi-media broadcast multicast services (MBMS) data to user equipments via relay nodes, according to one embodiment. In Figure 2, the system 200 includes a MBMS control entity (MCE) 202, a MBMS gateway 204, a donor eNodeB (DeNB) 206, a first set of user equipments 208A-N, relay nodes 210A-N, a second set of user equipments 212A-N, a Broadcast Multicast Service Centre (BM-SC) 126, and a mobility management entity (MME) 228. The MCE 202 is connected to the DeNB 206 via a M2 interface 214 while the MBMS gateway 204 is connected to the DeNB 206 via a M1 interface 216. The DeNB 106 connects the relay nodes 210A-N via an Un interface 218. The user equipments 208A-N and 212A-N are connected to DeNB 206 and the relay nodes 210A-N through an air interface 220.

The MCE 202 is a logical entity responsible for allocation of time and frequency resources for MBMS data transmission to the DeNB 206 in a MBSFN area via the M2 interface 214. The BM-SC 226 is a functional entity configured for providing MBMS to user equipments. The MBMS gateway 204 is operable for broadcasting synchronization packets received from the BM-SC 226 to eNBs (e.g., including the DeNB 206) within a MBSFN area as well as MBMS session management (e.g., Session Start and Session Stop) via the M1 interface 216. The M1 interface 216 is an interface between the MBMS gateway 204 and the DeNB 206 that makes use of IP multicast protocol for delivery of synchronization packets to the DeNB 206.

According to the present invention, the DeNB 206 includes a proxy MBMS gateway 222 and a proxy MCE 224. The proxy MBMS gateway 222 is configured for maintaining synchronized transmission of MBMS data to the user equipments 212A-N between different relay nodes 210A-N. In one embodiment, the proxy MBMS gateway 222 can transmit the MBMS data to the relay nodes 210A-N connected to the DeNB 206 over the Un interface 218. In another embodiment, the proxy MBMS gateway 224 is configured to transmit MBMS data to the relay nodes 210A-N over dedicated bearers targeting individual relay nodes 210A-N separately. The process carried out by the proxy MBMS gateway 222 is illustrated in greater detail in Figure 3.

The proxy MCE 224 is configured for controlling MBSFN configuration of the relay nodes 110A-N. In some embodiments, the proxy MCE 224 may determine number of user equipments under the control of relay nodes 210A-N and reporting the number of user equipments to the MCE 202 over the M2 interface 214. The process carried out by the proxy MCE 224 is illustrated in greater detail in Figure 4. Although, the proxy MBMS gateway 222 and the proxy MCE 224 are implemented as separate entities in the DeNB 206, one can envision that the proxy MCE 224 can be implemented in the proxy MBMS gateway 222.

Figure 3 illustrates a process flowchart 300 of an exemplary method of providing MBMS data to the user equipments 212A-N via the relay nodes 210A-N in a synchronized manner, according to one embodiment. At step 302, a synchronization delay associated with the relay nodes 210A-N in a MBSFN area is periodically evaluated by the proxy MBMS gateway 222 in the DeNB 206. The synchronization delay associated with the relay nodes 210A-N is determined based on delays encountered over the Un interface 218 between the DeNB 206 and the relay nodes 210A-N. At step 304, a time stamp is set in synchronization packets based on the synchronization delay associated with the relay nodes 210A-N. The time stamp information indicates start time for synchronized transmission of the MBMS data to the user equipments 208A-N and 212A-N in the MBSFN area over the air interface 220.

At step 306, resources are allocated to the relay nodes 210A-N for communicating MBMS data received from the MBMS gateway 204 to the relay nodes 210A-N. In one embodiment, a dedicated bearer resource reservation is initiated by the proxy MBMS gateway 222A-N for providing MBMS. In an alternate embodiment, a particular relay node may initiate dedicated bearer resource reservation for availing MBMS. Based on the resource reservation request, the proxy MBMS gateway 222 allocates the resources for communicating the MBMS data to the particular relay node.

At step 308, the synchronization packets including the MBMS data, the time stamp information, packet counter information and elapsed octet counter information is transmitted to the relay nodes 210A-N by the proxy MBMS gateway 222 using the allocated resources. Exemplary synchronization packet is illustrated in Figure 5A. Alternatively, the proxy MBMS gateway 222 may also transmit the synchronization packets without including the MBMS data to the relay nodes 210A-N as illustrated in Figure 5B.

When each of the relay nodes 210A-N receives the synchronization packets, the relay nodes 210A-N transmit the MBMS data in the synchronization packets to respective user equipments 212A-N based on the time stamp information. In other words, the time stamp information enables the relays nodes 210A-N to start transmitting the MBMS data in a synchronized manner. Also, the DeNB 206 starts transmitting the MBMS data to the connected user equipments 208A-N substantially simultaneously to the transmission of the MBMS data by the relay nodes 210A-N based on the time stamp information. This helps maintain synchronized transmission of MBMS data between the relay nodes 210A-N within a MBSFN area.

The above description explains a case scenario when the relay nodes 210A-N are part of a separate MBSFN area. When the relay nodes 210A-N are part of the same MBSFN area including eNBs (not shown) and the DeNB 206, the proxy MBMS gateway 222 ensures that the MBMS data is still transmitted to the user equipments by the eNBs, the DeNB 206 and the relays nodes 210A-N in synchronized manner. The is possible as the proxy MBMS gateway 222 communicates the synchronization delay associated with the relay nodes 210A-N to the MBMS gateway 206 over M1 interface 216. The MBMS gateway 206 considers the synchronization delay over the Un interface 218 while setting the time stamp in the synchronization packets transmitted to the eNBs, and the DeNBs in the same MBSFN area. In some cases, the BM-SC server 226 can also considers the synchronization delay over the Un interface 218 while setting the time stamp in the synchronization packets transmitted to the eNBs, and the DeNBs in the same MBSFN area.

Figure 4 is a process flowchart 400 illustrating an exemplary method of counting number of user equipments associated with each of the relay nodes 210A-N, according to one embodiment. At step 402, a counting request is sent to each of the relay nodes 210A-N by the proxy MCE 224. At step 404, number of user equipments under its control is determined by each of the relay nodes 210A-N. The relay nodes 110A-N may then transmit the counting response message over a MBMS control Channel (MCCH) implemented in the relay nodes 110A-N. At step 406, a counting response indicating the number of user equipments under its control is received from the respective relay node. At step 408, number of user equipments under control of the DeNB 206 and the number of user equipment associated with the relay nodes 210A-N is communicated to the MCE 202 over the M2 interface 214. This is the case when the relay nodes 210A-N are part of same MBSFN area as the DeNB 206. Alternatively, when the relay nodes 210A-N are part of the separate MBSFN area, the DeNB 206 communicates the number of user equipments under its control to the MCE 202 while the proxy MCE 224 in the DeNB 206 communicates the number of user equipments under the control of relay nodes 210A-N to the MCE 202.

Figures 5A and 5B are

schematic representations

500 and 550 illustrating synchronization data packets transmitted to the relay nodes 210A-N by the proxy MBMS gateway 222, according to one embodiment. In Figure 5A, the synchronization data packet 500 includes a synchronization header 502 and a MBMS payload 504. The synchronization header 502 mainly includes time stamp field 506, a packet counter field 508, and an elapsed octet counter field 510. The time stamp field 506 includes time stamp information modified based on the synchronization delay. The packet counter field 508 indicates total number of packet counter while the elapsed octet counter field 510 indicates elapsed octet counter. Further, the MBMS payload field 504 includes MBMS data. The synchronization packet 550 of Figure 5B is similar to the synchronization packet 500 of Figure 5A except that the synchronization packet 550 does not include the MBMS payload 504.

Figure 6 is a flow diagram 600 illustrating an exemplary method of initiation of a MBMS session for providing MBMS data to user equipments via the relay nodes 210A-N, according to one embodiment.

Figure 7 is a flow diagram 700 illustrating an exemplary method of initiation of a MBMS session for providing MBMS data to user equipments the relay nodes 210A-N, according to one embodiment.

Figure 8 is a flow diagram 800 illustrating an exemplary method of initiation of a MBMS session for providing MBMS data to user equipments the relay nodes 210A-N, according to one embodiment.

Figure 9 illustrates a block diagram of the DeNB 206 showing various components for implementing embodiments of the present subject matter. In Figure 9, the DeNB 206 includes a processor 902, memory 904, a read only memory (ROM) 906, a transceiver 908, a bus 910, a communication interface 912, a display 914, an input device 916, and a cursor control 918.

The processor 902, as used herein, means any type of computational circuit, such as, but not limited to, a microprocessor, a microcontroller, a complex instruction set computing microprocessor, a reduced instruction set computing microprocessor, a very long instruction word microprocessor, an explicitly parallel instruction computing microprocessor, a graphics processor, a digital signal processor, or any other type of processing circuit. The processor 902 may also include embedded controllers, such as generic or programmable logic devices or arrays, application specific integrated circuits, single-chip computers, smart cards, and the like.

The memory 904 may be volatile memory and non-volatile memory. The memory 904 includes the proxy MBMS gateway 222 and the proxy MCE 224 for providing MBMS data to the user equipments 212A-N via the relay nodes 210A-N, according to the embodiments of the present subject matter. A variety of computer-readable storage media may be stored in and accessed from the memory elements. Memory elements may include any suitable memory device(s) for storing data and machine-readable instructions, such as read only memory, random access memory, erasable programmable read only memory, electrically erasable programmable read only memory, hard drive, removable media drive for handling memory cards, Memory SticksTM, and the like.

Embodiments of the present subject matter may be implemented in conjunction with modules, including functions, procedures, data structures, and application programs, for performing tasks, or defining abstract data types or low-level hardware contexts. Machine-readable instructions stored on any of the above-mentioned storage media may be executable by the processor 902. For example, a computer program may include machine-readable instructions capable of providing MBMS data to user equipments 212A-N via the relay nodes 210A-N in a synchronized manner, according to the teachings and herein described embodiments of the present subject matter. In one embodiment, the computer program may be included on a storage medium and loaded from the storage medium to a hard drive in the non-volatile memory.

It is appreciated that, the components such as the transceiver 908, communication interfaces 912, the display 914, the input device 916, and the cursor control 918 are well known to the person skilled in the art and hence the explanation is thereof omitted.

The present embodiments have been described with reference to specific example embodiments, it will be evident that various modifications and changes may be made to these embodiments without departing from the broader spirit and scope of the various embodiments. Furthermore, the various devices, modules, selectors, estimators, and the like described herein may be enabled and operated using hardware circuitry, for example, complementary metal oxide semiconductor based logic circuitry, firmware, software and/or any combination of hardware, firmware, and/or software embodied in a machine readable medium. For example, the various electrical structure and methods may be embodied using transistors, logic gates, and electrical circuits, such as application specific integrated circuit.

Claims

A method of providing multi-media broadcast multicast services (MBMS) to user equipments in a Multi-Media Broadcast over a Single Frequency Network (MBSFN) environment via relay nodes, comprising:

periodically evaluating a synchronization delay associated with at least one relay node in a MBSFN area by a donor eNB (DeNB);

assigning resources to the at least one relay node for communicating multi-media broadcast multicast service (MBMS) data; and

transmitting MBMS data to the at least one relay node using assigned resources based on the synchronization delay associated with the at least one relay node.
The method of claim 1, further comprising:

periodically communicating the synchronization delay associated with the at least one relay node to a MBMS gateway over a M1 interface.
The method of claim 2, wherein the synchronization delay is evaluated based on delays encountered over an Un interface connecting the DeNB and the at least one relay node.
The method of claim 1, further comprising:

setting time stamp in at least one synchronization packet based on the synchronization delay associated with the at least one relay node, wherein the time stamp information indicates start time for synchronized transmission of the MBMS data to user equipments in the MBSFN area over an air interface.
The method of claim 1, further comprising:

transmitting the at least one synchronization packet including the time stamp information, packet counter information and elapsed octet counter information to the at least one relay node over an Un interface.
The method of claim 3, wherein transmitting the MBMS data to the at least one relay node based on the synchronization delay associated with the at least one relay node comprises:

transmitting the at least one synchronization packet to the at least one relay node, wherein the at least one synchronization packet includes the MBMS data, the time stamp information, packet counter information, and elapsed octet counter information.
The method of claims 4 and 5, wherein transmitting the at least one synchronization packet to the at least one relay node comprises:

relaying the MBMS data in the at least one synchronization packet to the user equipments by the at least one relay node based on the time stamp information.
The method of claim 1, wherein transmitting the MBMS data to the at least one relay node based on the synchronization delay associated with the at least one relay node comprises:

transmitting the MBMS data to the at least one relay node based on the synchronization delay such that the at least one relay node and the DeNB substantially simultaneously transmits the MBMS data to user equipments associated with the at least one relay node and user equipments directly connected to the DeNB in a synchronized manner.
The method of claim 1, further comprising:

determining a number of user equipments serviced by the at least one relay node and the DeNB respectively; and

communicating the number of user equipments directly served by the at least one relay node and the DeNB to a MBMS control entity (MCE) over a M2 interface.
An apparatus comprising:

a processor; and

memory coupled to the processor, wherein the memory comprises a proxy multi-media broadcast multicast services (MBMS) gateway capable of:

periodically evaluating a synchronization delay associated with at least one relay node in a Multi-Media Broadcast over a Single Frequency Network (MBSFN) area;

assigning resources to the at least one relay node for communicating multi-media broadcast multicast service (MBMS) data; and

transmitting MBMS data to the at least one relay node using assigned resources based on the synchronization delay associated with the at least one relay node such that the MBMS data is relayed to the user equipments by the at least one relay node in a synchronized manner.
The apparatus of claim 10, wherein the proxy MBMS gateway is configured for periodically communicating the synchronization delay associated with the at least one relay node to a MBMS gateway over a M1 interface.
The apparatus of claim 11, wherein the proxy MBMS gateway is configured for evaluates the synchronization delay based on delays encountered over an Un interface.
The apparatus of claim 10, wherein the proxy MBMS gateway is configured for setting time stamp in at least one synchronization packet based on the synchronization delay associated with the at least one relay node, wherein the time stamp information indicates start time for synchronized transmission of the MBMS data to user equipments in the MBSFN area over an air interface.
The apparatus of claim 13, wherein the proxy MBMS gateway is configured for transmitting the at least one synchronization packet including the time stamp information, packet counter information and elapsed octet counter information to the at least one relay node over an Un interface.
The apparatus of claim 13, wherein in transmitting the MBMS data to the at least one relay node based on the synchronization delay associated with the at least one relay node, the proxy MBMS gateway is configured for transmitting the at least one synchronization packet to the at least one relay node, wherein the at least one synchronization packet includes the MBMS data, the time stamp information, packet counter information, and elapsed octet counter information.
The apparatus of claim 10, wherein the memory further comprises a proxy MBMS control entity (MCE) configured for:

determining a number of user equipments serviced by the at least one relay node; and

communicating the number of user equipments directly served by the at least one relay node to a MCE over a M2 interface.